Social Media App Backend

A back-end REST API to drive a social media web application built with Node.js, Express and MySQL.

In order to run the application locally:

• Create a .env file and refer to the .env.example file in the project's root to fill it in.

• Create a new MySQL database and tables that are expected by the application. This can be done by opening the mysql command line program and running source sql/create.sql. Refer to the source code in the sql/ directory to understand how the database works.

• Install project dependencies by running npm install and start a development server with npm run dev.

Project overview

index.js
The application entry point that sets up necessary middleward, routes, and starts the server.

config.js
Reads from your .env file to configure the MySQL database connection, JWT secret keys, and the express server.

sql/
Scripts that you can run on the MySQL command line to set up a database for the application. Inspect how tables are constructed and their corresponding relationships.

routes/
Code that defines the API endpoints and their corresponding handler functions that are called when the application receives a request.

services/
Code that handles specific tasks such as interacting with the MySQL database and retreiving specific data. Functions in these modules are imported and used in the routes/ modules.

JWT authentication

Most of the API endpoints require the request to contain a valid JWT access token. This token can be obtained by creating a new user via the /api/register endpoint and inspecting the accessToken property in the JSON response. If you have already created a user, call the /api/login endpoint to obtain a new JWT access token.

Register a new user

Set up the following request in Postman or your favorite API platform:

• POST method to http://localhost:5000/api/register

• Input the following JSON for the request body:

  {
    "username": "<your username>",
    "password": "<your password>",
    "email": "<your email>"
  }
  

After submitting the request, inspect the accessToken field in the JSON response. Copy its value and use it in subsequent requests that require JWT authentication. See the following section (Authorization header) to understand how to do this.

Log in

Set up the following request in Postman or your favorite API platform:

• POST method to http://localhost:5000/api/login

• Input the following JSON for the request body:

  {
    "username": "<your username>",
    "password": "<your password>",
    "email": "<your email>"
  }
  

After submitting the request, inspect the accessToken field in the JSON response. Copy its value and use it in subsequent requests that require JWT authentication.

Authorization header

In order to access endpoints that require a JWT access token, add an authorization header in your request by setting the following key value pair:

Key: authorization
Value: Bearer <paste your access token>

API Endpoints

The following endpoints summarise the API:

POST    /api/register            Create a new user
POST    /api/login               Log in
POST    /api/logout              Log out
POST    /api/regresh             Generate a new JWT refresh token

GET     /api/users/:id           Get a user's data
PUT     /api/users/:id           Update a user's data
DELETE  /api/users/:id           Delete a user
PUT     /api/users/:id/follow    Follow a user
PUT     /api/users/:id/unfollow  Unfollow a user
GET     /api/users               Get all users (for testing)

POST    /api/posts               Create a new post
PUT     /api/posts/:id           Update a post
DELETE  /api/posts/:id           Delete a post
PUT     /api/posts/:id/like      Like or unlike a post
GET     /api/posts/timeline/all  Fetch posts for a user's timeline
GET     /api/posts/:id`          Get a post's data

MySQL Database

Some notes regarding the MySQL schema:

• A many-to-many relationship defines the following relationship between users. The followers_followings table that tracks who users are following and who they are being followed by.

• A many-to-many relationship defines which posts a user likes. A user can like many posts, and a post can be liked by many users. Therefore, a junction table called user_post_likes defines this relationship.

• A one-to-many relationship defines the connectio between a user and their posts. The posts table contains a user_id foreign key column which indicates who owns the post.